1. Field of the Invention
The present invention relates to a semiconductor light-emitting element that includes a substrate and a semiconductor layer provided over the substrate and including a p-type semiconductor layer, a light-emitting layer, and an n-type semiconductor layer. The present invention relates also to a method for producing such a semiconductor light-emitting element.
2. Description of the Related Art
Patent Document 1 discloses a structure shown in FIG. 9 as one example of a conventional semiconductor light-emitting element.
FIG. 9 is a schematic sectional view of the semiconductor light-emitting element disclosed in Patent Document 1. A conventional semiconductor light-emitting element 100 has a structure in which a bonding layer 102, a reflective electrode 103, an ohmic contact layer 104, a current blocking layer 105, an isolation layer 106, a semiconductor layer 107, and an n-side electrode 108 are provided on a support substrate 101. The semiconductor layer 107 includes a p-type semiconductor layer 111, a light-emitting layer 112, and an n-type semiconductor layer 113 that are stacked in this order from the bottom.
In the following description, a plane parallel to the substrate surface of the support substrate 101 is defined as an X-Y plane, and a direction perpendicular to the plane is defined as a Z direction. It is to be noted that the semiconductor light-emitting element 100 shown in FIG. 9 is an element from which light is extracted in an upward direction (Z direction) in the plane of paper.
The bonding layer 102 is a conductive material that is provided to improve adhesion between the support substrate 101 and the reflective electrode 103 when they are bonded together. The bonding layer 102 is made of, for example, solder. The reflective electrode 103 is made of a metal or alloy having a high reflectivity. The reflective electrode 103 reflects light emitted from the light-emitting layer 112 toward the support substrate 101 side (in a downward direction in the plane of paper) so that the light is guided to a light extraction surface provided on the n-side electrode 108 side. This is effective at improving light extraction efficiency.
The current blocking layer 105 is provided in a position vertically below the n-side electrode 108 so as to be in contact with the bottom surface of the semiconductor layer 107. The current blocking layer 105 is made of an insulating material or a material that forms a Schottky contact with the semiconductor layer 107. According to Patent Document 1, the current blocking layer 105 shall contain at least one selected from, for example, SiO2, SiOx, SiOxNy, Si3N4, Al2O2, TiOx, Ti, Al, and Cr.
The isolation layer 106 is an insulating layer provided for the purpose of ensuring insulation between adjacent elements when the semiconductor layer 107 is separated for element isolation. The isolation layer 106 is made of, for example, SiO2, SiN, or Al2O2.
The ohmic contact layer 104 is constituted from a conductive oxide film, such as ITO, having light permeability. The ohmic contact layer 104 is provided on the upper surface of the reflective electrode 103, and part of the upper surface of the ohmic contact layer 104 is in contact with the bottom surface of the semiconductor layer 107. More specifically, the ohmic contact layer 104 is in contact with the isolation layer 106 or the current blocking layer 105 without any contact with the semiconductor layer 107 in a position vertically below the n-side electrode 108, and is in contact with the semiconductor layer 107 in part of a region where the n-side electrode 108 is not provided vertically above the ohmic contact layer 104. The ohmic contact layer 104 forms an ohmic contact with the semiconductor layer 107 at its interface with the semiconductor layer 107.